1. Field of the Invention
The present invention relates to a mixer comprising duct mean and stirring vane means located within the duct means and being effective to act on a flow of fluid passing through the duct means such that the flow of fluid will repeatedly be divided and joined together to provide a desired stirring action.
2. Description of the Prior Art
For various industrial fields, it is very important to uniformly stir and mix different types of materials which mainly include liquid and gas or powder. Particularly, chemical treating and/or food processing industries desire a mixer which can mix materials more efficiently and uniformly.
The general mixing is effected by driving stirring vanes within a mixing vessel through a motor or the like. It is also well-known in the art to use a static type mixer in which a mixing can be performed only by flowing fluids to be mixed therethrough without any external drive. Such a static type mixer comprises a duct for inducting fluids to be mixed and a number of stirring vanes statically disposed within the duct, whereby the fluids to be mixed can repeatedly be divided and joined together as they flow through the duct. Thus, the mixing action can more efficiently be realized even if the length of the duct is relatively short. For the above reasons, such a static type mixer is extensively utilized through various kinds of industrial fields.
Thus, the static type mixer is advantageous in that an actually sufficient mixing action can efficiently be accomplished without any external drive. However, various fields of foodstuffs, paints and fine chemicals require a further uniform and efficient mixing action. Therefore, the prior art static mixer may be insufficient to meet such severe requirements.
Particularly, when it is wanted to mix powders having fine particle size, the prior art static mixer tends to create clogging between the inner wall of the duct and the stirring vanes. lf such clogging is released by any external pressure from either of the inlet or outlet of the duct, the mixer will perfectly be inoperative.
On the other hand, when stirring vanes are driven by a motor, an increased kinetic energy may be applied to the fluids to be mixed, so that their chemical properties will adversely be affected by the kinetic energy.
It is therefore desired to provide a new mixer which can overcome these problems in both the aforementioned systems.